Hi Mar,
Fornite is currently not supported on Linux due to its EasyAntiCheat feature. I'm sorry, I find myself in the same situation with my children.
I invite you to know the Steam platform with a variety of games for Linux.
SteamOS + Linux en Steam (steampowered.com)
For conventional phone calls, you'll need a VoIP app (Empathy?) and probably a paid account for use. You can also use apps with a proprietary network that allow calls with the disadvantage that the two speakers must use the same app (Telegram?) I'm not up to date on this, and I can be wrong.
Regards.